Passive stiffness and active deformation haptic output devices for flexible displays

ABSTRACT

A system includes a flexible display configured to display an image and a sensor connected to the flexible display. The sensor is configured to sense an amount of flexure of the flexible display. A haptic output device is connected to the flexible display and is configured to change a resistance to movement of a first portion of the flexible display relative to a second portion of the flexible display upon receipt of a haptic control signal. The system includes a processor in signal communication with the flexible display, the sensor and the haptic output device. The processor is configured to receive an output signal from the sensor based on the amount of flexure and generate the haptic control signal based on the output signal from the sensor.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority from U.S. ProvisionalPatent Application Ser. No. 61/816,605, filed Apr. 26, 2013, the entirecontent of which is incorporated herein by reference.

FIELD

The present invention relates to passive stiffness and activedeformation haptic output devices for flexible displays.

BACKGROUND

Flexible displays, which include digital displays that are bendable,foldable and/or rollable are being developed and may enable moreintuitive and realistic digital user interface interactions, similar tothose occurring in the real world. The use of haptics to augment andenhance such interactions has been limited. Most of the interactionsinvolving flexible displays are characterized by a continuous input inthe form of deformation gesture on the display, but such interactionsprovide the user with only passive haptics, which does not necessarilycorrespond to, or correlate with the user interface events in thedigital environment.

SUMMARY

It is desirable to enable different and additional haptic effects whenusers interact with flexible displays.

According to an aspect of the present invention, there is provided asystem that includes a flexible display configured to display an imageand a sensor connected to the flexible display. The sensor is configuredto sense an amount of flexure of the flexible display. A haptic outputdevice is connected to the flexible display and is configured to changea resistance to movement of a first portion of the flexible displayrelative to a second portion of the flexible display upon receipt of ahaptic control signal. The system includes a processor in signalcommunication with the flexible display, the sensor and the hapticoutput device. The processor is configured to receive an output signalfrom the sensor based on the amount of flexure and generate the hapticcontrol signal based on the output signal from the sensor.

In an embodiment, the haptic output device is constructed and arrangedto change a stiffness of a hinge formed between the first portion andthe second portion of the flexible display when at least one of the twoportions is moved towards the other of the two portions.

In an embodiment, the haptic output device is configured to lock thehinge when the first portion and the second portion are separated by apredetermined amount of space so that the two portions cannot moverelative to each other.

In an embodiment, the haptic output device is constructed and arrangedto assist with movement of the first portion relative to the secondportion when the sensor senses that the flexible display has beenflexed.

In an embodiment, the haptic output device is constructed and arrangedto oppose movement of the first portion relative to the second portionwhen the sensor senses that the flexible display has been flexed.

In an embodiment, the haptic output device includes a smart gel and anactivation element constructed and arranged to change a stiffness of thesmart gel upon receipt of the haptic control signal.

In an embodiment, the haptic output device includes a rheological fluidand an activation element constructed and arranged to change a viscosityor damping property of the rheological fluid upon receipt of the hapticcontrol signal.

In an embodiment, the haptic output device includes a shape memory alloyand an activation element configured to change a temperature of theshape memory alloy to return the shape memory alloy to its originalshape upon receipt of the haptic control signal.

According to an aspect of the invention, there is provided a method thatincludes sensing an amount of flexure of a flexible display configuredto display an image with a sensor, generating a haptic control signalbased on the sensed amount of flexure with a processor, and changing aresistance to movement of a first portion of the flexible displayrelative to a second portion of the flexible display with a hapticoutput device upon receipt of a haptic control signal.

In an embodiment, changing a resistance to movement includes changing astiffness of a hinge formed between the first portion and the secondportion of the flexible display when at least one of the two portions ismoved towards the other of the two portions.

In an embodiment, the haptic output device is configured to lock thehinge when the first portion and the second portion are separated by apredetermined amount of space so that the two portions cannot moverelative to each other.

In an embodiment, changing a resistance to movement includes reducingthe resistance and assisting with movement of the first portion relativeto the second portion when the sensor senses that the flexible displayhas been flexed.

In an embodiment, changing a resistance to movement includes increasingthe resistance to oppose movement of the first portion relative to thesecond portion when the sensor senses that the flexible display has beenflexed.

In an embodiment, the haptic output device includes a smart gel and anactivation element, and changing a resistance to movement includescausing the smart gel to stiffen upon receipt of the haptic controlsignal by the activation element.

In an embodiment, the haptic output device includes a rheological fluidand an activation element, and changing a resistance to movementincludes causing a viscosity or damping property of the rheologicalfluid to change upon receipt of the haptic control signal by theactivation element.

In an embodiment, the haptic output device includes a shape memory alloyand an activation element, and changing a resistance to movementcomprises causing the shape memory alloy to return to its original shapeupon receipt of the haptic control signal by the activation element.

These and other aspects, features, and characteristics of the presentinvention, as well as the methods of operation and functions of therelated elements of structure and the combination of parts and economiesof manufacture, will become more apparent upon consideration of thefollowing description and the appended claims with reference to theaccompanying drawings, all of which form a part of this specification.It is to be expressly understood, however, that the drawings are for thepurpose of illustration and description only and are not intended as adefinition of the limits of the invention. As used in the specificationand in the claims, the singular form of “a”, “an”, and “the” includeplural referents unless the context clearly dictates otherwise.

BRIEF DESCRIPTION OF THE DRAWINGS

The components of the following Figures are illustrated to emphasize thegeneral principles of the present disclosure and are not necessarilydrawn to scale. Reference characters designating correspondingcomponents are repeated as necessary throughout the Figures for the sakeof consistency and clarity.

FIG. 1 schematically illustrates a system in accordance with anembodiment of the invention;

FIG. 2 schematically illustrates a perspective view of an embodiment ofthe system of FIG. 1 in the form of a flexible user interface devicehaving a flexible display in a flat configuration;

FIG. 3 schematically illustrates a perspective view of the flexible userinterface device of FIG. 2 in a bent configuration;

FIG. 4 schematically illustrates a perspective view of the flexible userinterface device of FIG. 2 in a folded configuration;

FIG. 5 schematically illustrates a processor of the system of FIG. 1;

FIG. 6 schematically illustrates a cross-sectional view of an embodimentof the system of FIG. 1 in the form of a flexible user interface devicehaving a flexible display in a bent configuration;

FIG. 7 schematically illustrates a cross-sectional view of an embodimentof the flexible user interface device of FIG. 6;

FIG. 8 schematically illustrates a perspective view of an embodiment ofthe system of FIG. 1 in the form of a flexible user interface devicehaving a flexible display in a bent configuration;

FIG. 9 schematically illustrates a perspective view of an embodiment ofthe system of FIG. 1 in the form of a foldable user interface devicehaving a flexible display and a rigid housing in an open position; and

FIG. 10 schematically illustrates a perspective view of an embodiment ofthe user interface device of FIG. 9 in a closed position.

DETAILED DESCRIPTION

FIG. 1 is a schematic illustration of a system 100 in accordance with anembodiment of the invention. As illustrated, the system 100 includes aprocessor 110, a memory device 120, and input/output devices 130, whichare interconnected via a bus 140. In an embodiment, the input/outputdevices 130 may include a touch screen device 150, a haptic outputdevice 160 and/or other input devices that receive input from a user ofthe system 100 and output devices that output information to the user ofthe system 100. In an embodiment, the system 100 may be a user interfacedevice in the form of a touch mobile or tablet device that includes allof the components illustrated in FIG. 1 in a single integrated device.In an embodiment, the system 100 is a single, integrated, flexibledevice that may be flexed, bent, rolled, folded, etc., as discussed infurther detail below.

The touch screen device 150 may be configured as any suitable userinterface or touch/contact surface assembly and may be configured forphysical interaction with a user-controlled device, such as a stylus,finger, etc. In some embodiments, the touch screen device 150 mayinclude at least one output device and at least one input device. Forexample, as illustrated the touch screen device 150 includes a visualdisplay 152 configured to display, for example, images and a touchsensitive screen comprising at least one sensor 154 superimposed thereonto receive inputs from a user's finger or stylus controlled by the user.The visual display 152 may include a high definition display screen.

In various embodiments, the haptic output device 160 is configured toprovide haptic feedback to the user of the system 100 while the user isin contact with a least a portion of the system 100. For example, thehaptic output device 160 may provide haptic feedback to the touch screendevice 150 itself to impose a haptic effect when the user is in contactwith the touch screen device 150 and/or to another part of the system100, such as a housing containing at least the input/output devices 130.As discussed in further detail below, the haptic effects may be used toenhance the user experience when interacting with the system 100.

The haptic feedback provided by the haptic output device 160 may becreated with any of the methods of creating haptic effects, such asvibration, deformation, kinesthetic sensations, electrostatic orultrasonic friction, etc. In an embodiment, the haptic output device 160may include non-mechanical or non-vibratory devices such as those thatuse electrostatic friction (“ESF”), ultrasonic surface friction (“USF”),or those that induce acoustic radiation pressure with an ultrasonichaptic transducer, or those that use a haptic substrate and a flexibleor deformable surface, or those that provide thermal effects, or thosethat provide projected haptic output such as a puff of air using an airjet, and so on. The haptic output device 160 may include an actuator,for example, an electromagnetic actuator such as an Eccentric RotatingMass (“ERM”) in which an eccentric mass is moved by a motor, a LinearResonant Actuator (“LRA”) in which a mass attached to a spring is drivenback and forth, or a “smart material” such as piezoelectric materials,electro-active polymers or shape memory alloys, a macro-composite fiberactuator, an electro-static actuator, an electro-tactile actuator,and/or another type of actuator that provides a physical feedback suchas vibrotactile feedback. Multiple haptic output devices 160 may be usedto generate different haptic effects.

The processor 110 may be a general-purpose or specific-purpose processoror microcontroller for managing or controlling the operations andfunctions of the system 100. For example, the processor 110 may bespecifically designed as an application-specific integrated circuit(“ASIC”) to control output signals to the haptic output device 160 toprovide haptic effects. The processor 110 may be configured to decide,based on predefined factors, what haptic effects are to be generatedbased on a haptic signal received or determined by the processor 110,the order in which the haptic effects are generated, and the magnitude,frequency, duration, and/or other parameters of the haptic effects. Theprocessor 110 may also be configured to provide streaming commands thatcan be used to drive the haptic output device 160 for providing aparticular haptic effect. In some embodiments, the processor 110 mayactually include a plurality of processors, each configured to performcertain functions within the system 100. The processor 110 is describedin further detail below.

The memory device 120 may include one or more internally fixed storageunits, removable storage units, and/or remotely accessible storageunits. The various storage units may include any combination of volatilememory and non-volatile memory. The storage units may be configured tostore any combination of information, data, instructions, software code,etc. More particularly, the storage units may include haptic effectprofiles, instructions for how the haptic output device 160 is to bedriven, or other information for generating haptic effects.

FIG. 2 illustrates an embodiment of the system 100 in the form of a userinterface device 200 that includes a flexible display 210. Asillustrated in FIG. 3, the entire user interface device 200 is flexibleand can be bent with the flexible display 210. In an embodiment, theuser interface device 200 may be bent at a hinge 220 and folded suchthat a first portion 212 of the flexible display 210 and a secondportion 214 of the flexible display 210 may contact each other or comeclose to contacting each other, as illustrated in FIG. 4. A sensor 230embedded in or otherwise connected to the flexible display 210 isconfigured to sense the flexure of the flexible display 210. The sensor230 may include a strain gauge or any other type of sensor that isconfigured to sense the flexure of the flexible display 210 and/ormovement of the first portion 212 of the flexible display 210 relativeto the second portion 214 of the flexible display 210.

FIG. 5 illustrates an embodiment of the processor 110 described above inmore detail. The processor 110 may be configured to execute one or morecomputer program modules. The one or more computer program modules mayinclude one or more of a sensor module 112, a determination module 114,a haptic output device control module 116, and/or other modules. Theprocessor 110 may also include electronic storage 118, which may be thesame as the memory device 120 or in addition to the memory device 120.The processor 110 may be configured to execute the modules 112, 114,and/or 116 by software, hardware, firmware, some combination ofsoftware, hardware, and/or firmware, and/or other mechanisms forconfiguring processing capabilities on processor 110.

It should be appreciated that although modules 112, 114, and 116 areillustrated in FIG. 2 as being co-located within a single processingunit, in embodiments in which the processor 110 includes multipleprocessing units, one or more of modules 112, 114, and/or 116 may belocated remotely from the other modules. The description of thefunctionality provided by the different modules 112, 114, and/or 116described below is for illustrative purposes, and is not intended to belimiting, as any of the modules 112, 114, and/or 116 may provide more orless functionality than is described. For example, one or more of themodules 112, 114, and/or 116 may be eliminated, and some or all of itsfunctionality may be provided by other ones of the modules 112, 114,and/or 116. As another example, the processor 110 may be configured toexecute one or more additional modules that may perform some or all ofthe functionality attributed below to one of the modules 112, 114,and/or 116.

The sensor module 112 is configured to receive an input signal from thesensor 154 that is generated when the sensor 154 detects an input from auser of the system 100. In embodiments in which there are multiplesensors, the sensor module 112 is configured to receive and processinput signals from the multiple sensors. The sensor module 112 may beconfigured to determine whether the sensed input is an intentional inputor merely an inadvertent touch to the touch screen device 150 bycomparing the strength of the input signal or the pattern or location ofthe input signal to a predetermined threshold strength that correspondsto an intentional input. In addition, the sensor module 112 isconfigured to receive an input signal from the sensor 230 that isgenerated when the flexible user interface device 200 is flexed, whichmay occur when the user interface device 200 is bent, folded or rolled,for example. The sensor module 112 is also configured to send a signalto the determination module 114 for further processing.

The determination module 114 is configured to determine what wasintended by the user when providing an input to the sensor 154. Forexample, the user may touch a certain location of the touch screendevice 150 or provide a particular gesture to the touch screen device150, or bend the user interface device 200 in a certain manner thatindicates that a certain function is to be performed by the userinterface device 200. The determination module 114 may be programmedwith a library of predetermined gestures and touch locations on thetouch screen device 150 so that when the user touches a particularlocation on the touch screen device 150 or provides a gesture to thetouch screen device 150, the determination module 114 may determine acorresponding output. When the user flexes the system 100 (or userinterface device 200), if the sensor 154, 230 senses an amount offlexure that exceeds a predetermined amount, it may be determined thatthe user is in the process of folding the system 100 or user interfacedevice 200, for example at the hinge 220, and the flexible display 210should be powered off. In addition, the determination module 114 mayalso output a signal to the haptic output device control module 116 sothat a haptic effect in accordance with embodiments of the inventiondescribed below may be provided to the user.

The haptic output device control module 116 is configured to receive theoutput signal from the determination module 114 and determine the hapticeffect to be generated by the haptic output device 160, based on thesignal generated by the determination module 114.

In an embodiment of the invention, the system 100 may be a flexible userinterface device 600, as illustrated in FIG. 6 that includes a hapticoutput device 610 that is embedded within a hinge 620 of the flexibleuser interface device 600. The hinge 620 of the flexible user interfacedevice 600 may be considered to be the location where a first portion630 and a second portion 640 of the flexible user interface device 600may pivot or rotate and move towards each other, or away from eachother, as the flexible user interface device 600 is flexed or bent orfolded, as illustrated in FIG. 6. In an embodiment, the flexible userinterface device 600 may be configured to fold at the hinge 620 when thetwo portions 630, 640 of the device 600 located on opposite sides of thehinge 620 are brought towards each other.

In an embodiment, the haptic output device 610 may be embedded within abody or housing 650 of the device 600 that supports a flexible display660 or may be coupled to the body or housing 650 of the device 600. Thehaptic output device 610 may be in the form of a fluidic actuator thatincludes a smart gel or rheological fluid and an activation element, asdiscussed in further detail below.

A smart gel, which includes a fluid basis (typically water) within orsurrounding a matrix of polymer, is characterized by its ability toquickly change mechanical and/or structural properties upon exposure tocertain physical and/or chemical external stimuli, such as an electricor magnetic field, temperature, (UV-) light, shaking, pH variation, etc.The response or reaction of smart gels to such stimuli is expansion orcontraction, which is typically caused by the polymer matrix becomingmore or less hydrophilic and absorbing or releasing more molecules fromor to the gel. By making non-homogeneous gels with different rates ofexpansion/contraction, a controlled stimulus (e.g. voltage-controlledelectric field) may cause the gel to bend and/or stiffen by a certaincontrolled amount. A subclass of smart gels is so-called shake gels,which stiffen when exposed to mechanical impact or when strongly shaken.

A smart gel may comprise a temperature-sensitive hydrogel that isconfigured to expand and stiffen when heated above a thresholdtemperature, and contract and relax when cooled down below the thresholdtemperature. The smart gel may be configured to respond to anotherstimulus besides temperature, such as electrical current, light, salt,and chemical stimuli. The system 100 may include activating elements tointroduce an appropriate stimulus to achieve a desired response by thesmart gel. For example, if the smart gel is configured to deform as afunction of light, the system 100 may include an element to stimulatethe smart gel by directing light toward the smart gel. In an embodimentin which the smart gel responds to a chemical stimulus, an injectiondevice may be used to introduce a chemical agent to the smart gel, suchas an agent that changes the smart gel pH, a salt, glucose, ions, etc.In an embodiment in which the smart gel responds to an electricalstimulus, wires or other elements may be embedded in the smart gel orelectrodes may be used to direct current through the smart gel and/or toapply an electric field to the smart gel.

Rheological fluids are another category of fluidic actuators andtypically include iron particles suspended in oil or watery fluid. Uponexposure to electric (for electro-rheological fluids) or magnetic (formagneto-rheological fluids) fields, the order of molecules in the liquidaligns itself to the field main axis. This phenomenon causes the overalldamping and/or viscosity of the fluid to change, up to the point that ifthe field strength is high enough, the rheological fluid may turn into asolid fairly quickly.

Returning to FIG. 6, in an embodiment, the flexible user interfacedevice 600 may not have a predefined hinge 620. Instead, the areacorresponding to the hinge 620 in FIG. 6 may be filled with smart gel orrheological fluid. If the smart gel or rheological fluid is activated,as described above, and increased in stiffness, a temporary hinge may becreated to divide the device 600 into two halves, such as the firstportion 630 and the second portion 640, which can rotate around thenewly created hinge. As soon as the actuation turns off, the hinge maysoften and eventually disappear.

In an embodiment, a layer 710 filled with a smart gel or rheologicalfluid and flexible electrodes 712, 714 on each side (to form a hapticoutput device in the form of a fluidic actuator 720) may extend acrossthe whole surface of the body 650 under the flexible display 660, asschematically illustrated in FIG. 7. By activating and therebystiffening an arbitrary strip of the fluid, a temporary hinge can becreated at an arbitrary location, with an arbitrary orientation(horizontal, lateral, diagonal, curved, etc.).

FIG. 8 illustrates an embodiment of the system 100 in the form of aflexible user interface device 800 that includes a plurality of hapticoutput devices 810 embedded in a flexible body 820 and a hinge location830 of the device 800. As illustrated, the haptic output devices 810extend from a first portion 840 of the body 820, across the hingelocation 830 to a second portion 850 of the body 820. Although fivehaptic output devices 810 are illustrated, more or less haptic outputdevices 810 may be used. The illustrated embodiment is not intended tobe limiting in any way. The haptic output devices 810 may include shapememory alloys, such as in the form of shape memory alloy fibers, and oneor more activation elements configured to heat the shape memory alloyfibers, which may cause the fibers to return to their original shape.For example, if the user interface device 800 is flexed to the conditionillustrated in FIG. 8, which may be sensed by a sensor embedded in thedevice, the processor 110 may generate a haptic control signal thatactivates the activation element, for example, passing current throughthe element, and cause the shape memory alloy fiber(s) to straighten,which would cause the user interface device 800 to move back to asubstantially flat configuration, similar to the configurationillustrated in FIG. 2.

In an embodiment, by having the shape memory alloy fibers extend aroundthe hinge, as illustrated in FIG. 8, the shape memory alloy fibers maybe configured to resist against elongation and thus generate a hapticeffect that opposes the two halves of the device from closing. In anembodiment, upon activation, the shape memory alloys may shorten,thereby leading to an active kinesthetic haptic effect in the form thatmay bring the two portions 840, 850 of the device 800 towards each otherand fold the device 800 at the hinge location 830. In an embodiment, thehaptic output devices 810 may include macro fiber composite (“MFC”)piezoelectric fibers that are embedded around and within the hingelocation 820 of the device 800.

FIG. 9 illustrates an embodiment of the system 100 in the form of a userinterface device 900 that includes a rigid housing 910 that supports aflexible display 920. At least one haptic output device (not shown inFIG. 9) may be used to assist the user to move a first portion 912 ofthe housing 910 towards a second portion 914 of the housing 910 that ison an opposite side of a hinge 930 provided by the flexible display 920so that the user interface device 900 may be moved from an open state,as illustrated in FIG. 9, to a closed state, as illustrated in FIG. 10.Once the user interface device 900 is in the closed state, a hapticoutput device in accordance with embodiments of the invention describedherein may be actuated so that the hinge 930 locks the user interfacedevice 900 in the closed position. In an embodiment, the hinge 930 ofthe flexible display 920 may be haptically enabled using a combinationof haptic output devices in the forms of an electric motor and a smartgel based actuator. The electric motor may be used to create activedeformation and assist with the opening or closing of the foldabledevice, while the smart gel based actuator may lock the configuration inplace, thereby preventing the foldable display from opening or closing.

In an embodiment, the rotating motion of the first and second portionsof the display or device around the hinge 930 may involve frictionaland/or sliding contact among the subcomponents in the hinge. Theeffective friction coefficient seen by the subcomponents may bemodulated (e.g., reduced) if ultrasound vibration is applied on theirsurfaces, which may allow for a hinge-based programmable resistance tobe created and displayed to the user as he/she is opening or closing thetwo halves of the flexible display.

In an embodiment of the invention, a fluidic actuator based on smartgels or rheological fluid, described above, may be mounted to the backsurface of a rollable display. Driving such an actuator may produceprogrammable resistive (passive) or active haptic effects on the rollingdegree of freedom of the display.

In an embodiment, the haptic output device may include anelectromechanical actuator to provide a mini resistive haptic effectalong a large hinge. In an embodiment, an ultrasonic motor may belocated in an area with high friction and may generate ultrasonicvibrations when activated to reduce the friction. In an embodiment, ashape memory alloy in the form of a wire may be used to oppose usermovement. In an embodiment, an actuator configured to deform and sustainthe deformation when the user interacts with the device, such as apiezoelectric or MFC actuator, may be used. In an embodiment, a smartgel or rheological fluid that is embedded in the back of the display maybe configured to change the stiffness or damping of the surface of thedisplay when activated. In an embodiment, the haptic output device maybe configured to generate haptic effects with faster dynamics. Forexample, the haptic output device may be configured to generate arelatively fast “pop”-like haptic effect that simulates the sensation of“snapping” a foldable device open and/or closed, such as when a laptopcomputer is opened or closed. Haptic effects may be generated using oneor a combination of the above-described technologies, in accordance withembodiments of the invention described herein.

Embodiments of the invention described above may be used to generateboth passive and active haptic effects, depending on a mode ofoperation. As used herein, “passive” haptic effects on the flexibledisplay may be generated by a change in mechanical stiffness/damping ofthe haptic output device embedded in the hinge or body of the device,and “active” haptic effects on the flexible display may be generatedwhen the haptic output device that is embedded in the hinge or body ofthe device actively bends the display.

Passive haptic effects may cause the perceived structuralstiffness/damping of the display to change, which allows for deliveringprogrammable structural resistance against deformation gestures (e.g.,bending the display) applied by the user. In addition, the passivekinesthetic haptic effects that are created may be used to enable avariety of interaction parameters and/or schemes. For example, in anembodiment, a controlled and gradual increase of the perceived stiffnessor firmness and damping factor of the display (versus its physicalvalue) may be generated. In an embodiment, a controlled and gradualdecrease of the perceived stiffness/damping from its physical value maybe generated by applying bending force towards the bending direction andthus facilitating the gesture and interaction for the user.

In a passive mode of operation, programmable resistance haptic effectsmay be delivered to the user as he/she bends or folds the device. Thisprogrammable resistance may be generated by driving the haptic outputdevice located in the hinge in a programmable manner, for example byexposing the smart gel or rheological fluid to a controlled electric ormagnetic field. Based on this configuration, a vast array of kinesthetichaptic effects and schemes may be enabled, which may increase thebreadth and depth of gestures and interactions involving flexibledisplays. For example, in an embodiment, a controlled and gradualincrease of the perceived damping factor of the display, as opposed toits physical value, may be generated. In an embodiment, mechanicaldetents during the bending motion may be generated, as long as theresponse time of the haptic output device is faster than the bendinggesture of the user. In an embodiment, the locking or holding (i.e.solidifying) of the display in a certain position may be generated. Inan embodiment, the range of the bending and/or the extent of the bendingmay be limited to a certain threshold. In an embodiment, an isolated,locally rigid section or patch or line on the display may be created. Inan embodiment, the deformation restoration rate, i.e. how fast/slow adeformed part springs back to its neutral state, if restored back atall, may be adjusted.

With active haptic effects, the device/display itself may actively applyforce along the deformation degree of freedom (e.g., bending). Thisforce may be opposite or in line with the external gesture force appliedby the user (if any), and may or may not result in actual deformation(i.e. shape change) of the device and display.

In the active mode of operation, the haptic output device may generate abending or folding force on the display, which, as opposed to thepassive mode, is not a pure resistance. The active mode haptic effectsmay be enabled, for example, with electromechanical actuators, shapememory alloys, MFC actuators, etc.

Embodiments of the present invention may provide an advantage byproviding an increase in flexibility of the haptic output device byusing smart gels, rheological fluids, shape memory alloys, MFC, etc.,and thus its compatibility with flexible surfaces and compact design. Inaddition, embodiments of the invention may satisfy the space constraintsin mobile user interface devices by embedding the haptic output devicein the hinge or surface of the device, which may provide a potentialpower savings by using a combination of actuation techniques. Forexample, a DC motor may be used to rotate portions of the flexible userinterface device, while a smart gel or an electro-rheological fluid maybe used to lock the configuration in place.

Embodiments of the invention that provide programmable kinesthetichaptic effects on flexible displays by using the actuation componentsdescribed herein may expand the breadth and depth of the userinteractions and enhance the user experience with flexible displays. Bycontrolling the resistance or stiffness of the display, the utility ofthe display may be facilitated. For example, typing on a touchscreen maybe easier if the device is rigid and zooming an image output by theflexible display may be easier by bending the display, which requires asofter, less rigid display. In addition, by reducing the perceiveddeformation firmness and assisting the user by applying a bending forcein the direction of a bending gesture, the user may experience lessfatigue.

Embodiments of the present invention may enable several hapticexperiences, including controlled and gradual increase of the perceiveddamping factor of the display, mechanical detents on bending motion,locking/holding (solidifying) the display in a certain position,limiting the range of bending range and extent to a certain threshold,creating isolated, locally rigid sections/patches/lines on the display,and adjusting the deformation restoration rate, i.e. how fast or slowthe deformed parts spring back to their neutral state, if restored backat all.

The embodiments described herein represent a number of possibleimplementations and examples and are not intended to necessarily limitthe present disclosure to any specific embodiments. Instead, variousmodifications can be made to these embodiments as would be understood byone of ordinary skill in the art. Any such modifications are intended tobe included within the spirit and scope of the present disclosure andprotected by the following claims.

What is claimed is:
 1. A system comprising: a flexible displayconfigured to display an image; a sensor connected to the flexibledisplay, the sensor configured to sense an amount of flexure of theflexible display and transmit an output signal associated with theamount of flexure; a haptic output device connected to the flexibledisplay, the haptic output device configured to change a resistance tomovement of a first portion of the flexible display relative to a secondportion of the flexible display in response to a haptic control signal;and a processor in signal communication with the flexible display, thesensor, and the haptic output device, the processor configured to:receive the output signal from the sensor; determine a haptic effectconfigured to assist flexure of the flexible display based on the outputsignal from the sensor; generate the haptic control signal based on thehaptic effect; and transmit the haptic control signal to the hapticoutput device.
 2. The system according to claim 1, wherein the processoris configured to cause the haptic output device to change a stiffness ofa hinge formed between the first portion and the second portion of theflexible display in response to at least one of the two portions beingmoved towards the other of the two portions.
 3. The system according toclaim 2, wherein the processor is configured to cause the haptic outputdevice to lock the hinge in response to the first portion and the secondportion being separated by a predetermined amount of space so that thetwo portions cannot move relative to each other.
 4. The system accordingto claim 1, wherein the processor is configured determine the hapticeffect configured to assist with the flexure of the flexible display inresponse to the output signal from the sensor indicating that theflexible display has been flexed.
 5. The system according to claim 1,wherein the processor is configured determine a haptic effect configuredto resist against the flexure of the flexible display in response to theoutput signal from the sensor indicating that the flexible display hasbeen flexed.
 6. The system according to claim 1, wherein the hapticoutput device comprises a smart gel and an activation elementconstructed and arranged to change a stiffness of the smart gel inresponse to the haptic control signal.
 7. The system according to claim1, wherein the haptic output device comprises a rheological fluid and anactivation element constructed and arranged to change a viscosity ordamping property of the rheological fluid in response to the hapticcontrol signal.
 8. The system according to claim 1, wherein the hapticoutput device comprises a shape memory alloy and an activation elementconfigured to change a temperature of the shape memory alloy to returnthe shape memory alloy to its original shape in response to the hapticcontrol signal.
 9. A method comprising: receiving, from a sensor and bya processor, a sensor signal associated with an amount of flexure of aflexible display configured to display an image; determining, by theprocessor, a haptic effect configured to assist with a flexure of theflexible display based on the sensor signal; generating, by theprocessor, a haptic control signal based on the haptic effect; andtransmitting, by the processor, the haptic control signal to a hapticoutput device configured to change a resistance to movement of a firstportion of the flexible display relative to a second portion of theflexible display in response to the haptic control signal.
 10. Themethod according to claim 9, further comprising changing a resistance tomovement by changing a stiffness of a hinge formed between the firstportion and the second portion of the flexible display in response to atleast one of the two portions being moved towards the other of the twoportions.
 11. The method according to claim 10, further comprisinglocking the hinge in response to the first portion and the secondportion being separated by a predetermined amount of space so that thetwo portions cannot move relative to each other.
 12. The methodaccording to claim 9, further comprising determining the haptic effectconfigured to assist with the flexure of the flexible display inresponse to the sensor sensing the flexible display has been flexed. 13.The method according to claim 9, further comprising determining a hapticeffect configured to resist against the flexure of the flexible displayin response to the sensor sensing the flexible display has been flexed.14. The method according to claim 9, wherein the haptic output devicecomprises a smart gel and an activation element, and wherein changing aresistance to movement comprises causing the smart gel to stiffen inresponse to the haptic control signal by the activation element.
 15. Themethod according to claim 9, wherein the haptic output device comprisesa rheological fluid and an activation element, and wherein changing aresistance to movement comprises causing a viscosity or damping propertyof the rheological fluid to change in response to the haptic controlsignal by the activation element.
 16. The method according to claim 9,wherein the haptic output device comprises a shape memory alloy and anactivation element, and wherein changing a resistance to movementcomprises causing the shape memory alloy to return to its original shapein response to the haptic control signal by the activation element. 17.The system according to claim 2, wherein the processor is furtherconfigured to: transmit a haptic signal to another haptic output deviceconfigured to modulate a coefficient of friction associated with thehinge by applying ultrasonic vibrations to the hinge.
 18. The systemaccording to claim 1, wherein the haptic effect is configured tosimulate a sensation of snapping a foldable device open or closed. 19.The system according to claim 1, wherein the haptic effect comprisesgradually increasing or gradually decreasing a damping factor of theflexible display in an amount associated with the amount of flexure ofthe flexible display.
 20. The system according to claim 1, wherein theprocessor is further configured to: determine that an input detected bythe sensor is an intentional input or an inadvertent input based on theoutput signal from the sensor.